Sound-box



M. KRAUSS.

SOUND BOX.

APPLICATION FILED APR. 17, 1920.

Patented Nov. 23, 1920.

2 SHEETS-SHEET l- 6 0 LIME- 2-2! F/GA T l E N TOR.

MAX KRA'USS, F PHILADELPHIA,

UNITED STATES TRUSTEE, OF PHILADELPHIA, PENNSYLVANIA.

PATENT OFFE'Q'ZIZL.

PENNSYLVANIA, 'As-sIeNoR To raANxLIN E. BARR,

' SOUND-BOX.

To all whom it mag lconcern: a

Be it known that I, Max KRAUss, a citizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and use ful Sound-Box, of which the following is a specification.

My invention relates in general to sound boxes for talking machines but is applicable with great advantage to boxes which comprise a dished or bulged diaphragm, that is to say a diaphragm having a concavo-convex form with the convexity facing outward. 1 i

The object of my invention is to employ a preferably but not necessarily dished diaphragm with a sound box of special and novel construction, the casing of which embodies, and may be said to be essentially composed of, a vibratory back made of mica or equivalent vibratory substance, so that I between the inner face of the diaphragm and the fronting face of said back there exists a sound chamber, essentially and so to speak, entirely composed of vibratory material,

within which the entering sound waves oca casionthe vibration not only of the dia phragm, but also of the back or'rearface' of the sound box itself, with the result that the acoustic properties of the sound box as an entirety are greatly improved. I With the foregoing objects inview myinvention comprehends a sound box of the character typically represented in; the ac; companying drawings and hereinafter described, the features :which Iclaima's novel being definitely specified in the claimsli v For the purpose of illustrating my inven- 'tion, I have shown in the drawingstwo typical embodiments of-it,'which'have given in practice novel and satisfactory results',---

.each of the said embodiments illustratingthe same constructions'o far asits essential features'are concerned, and'the difference being only in such mechanical features of assem blage of the operative elements aswould be obvious to anyskilled workman.

- Referring to the drawings, i f

Figure' I represents a front elevational view of a sound box embo'dyingmy inven- Fig, 2 represents a transverse, sectional elevation of the sound box represented in Fig. 1, the dimensions, for clearer illus Specification of Letters Patent. Patented NOV, 23, 1920,

Application filed April 17, 192a; Serial No. 374,542.

tr ation, beingenlarged, and the section taken. on line 2-2 of-Fig. 1; 1 I

Fig. 8 represen s in transverse, sectional detail a modified form of the separating ring represented in 'Eig. 2, removed from the sound box; v VF 1g. 4: similarly represents another modr' fied'form of saidseparating ring, likewise removed;

Fig. 5 represents a front, elevational view similarto thatof Fig. l of a modified form a separating ring'in the form of twoknifeedged rings,-which in-their mounting illustratedin Fig, 6, serve, when desired, to effect the dishing'of the diaphragm. 1

Similar numerals of: reference indicate corresponding parts.

Referring to the drawings 1 andQ designate casing rings, between which are embraced the peripheral edges of a diaphraginB, andialsoythe peripheraliedges of a back or rear face 4t of the sound box. The diaphragm, as usual, is composed of mica or equivalent vibratory substance, and the rear face of the soundfbox is alsopas stated," composedof mica or similar substance. y

i A separating ring I as ofsdiainond-shaped cross-section, which is of a diameter slightly less than that of the diaphragm and the back face of the sound first four figures of the 5, illustrated in i i box,-"is interposed between said diaphragm and said back face,

A plura'lity of fasteniiigs such the bolts 6' bearrupon opposite "faces of the casing rings 1 and 2, through apertures 1n which as e shownin Fig. 2, they pass, and effect the clamping together of the diaphragm and of the back or rear. face ofthe soundbox, so I as to effect the organlzatlon ofacas ng'as a,

composite whole.

7 designates a caslng or tone tube to which the back facei'of the sound box is. attached and by means of which any usual or preferred connectionwith the tonearm of the talking machine is effected;

.- The connection or support ofthistube i With relation to the back face otthe -sound box is conveniently through an outwardly extending flange 8 formedatthe upper orifice of the tube, a plurality of fastening devices such as the bolts 9 and an" annular washer 10, as shown in Fig. 2.

ll designates the operating arm or lever of the stylus, secured in any usual or preferred manner, as at 12, to the diaphragm. V1?) is the rocking bar ofthe arm .11, whichis susceptible of the usual vibratory or rocking movement by'being mountedin bearings 14, of which any well known type 'mayibe used. 15 designatesastylus-bar andsocket, and 16 the stylus. X r

In :Figs. 3 and 4 the separating ring instead of being diamond-shaped in cross.- section, is elliptical,'in Fig. 3 the longer axis'of'the ellipse'being vertical and-in Fig. 4 horizontal. V

The functionof theseparating ring being simply to peripherally separate the dias phragm and the vibratoryback face of the sound'box andform between them a sound chamber, it is immaterial what its crosssectional form may be, although it is prefen able that it should have bearing or separating edges which are not fiat.

It is also immaterial of what substance the'ring be formed,--although I prefer to make it of metal.

In the =modification represented in Figs. 5,6 and 7, the peripherahedge of the vibratory back face 4i of the sound box, is encompassed by an inclc-sing wall 17, an internally extending flange 18 of which is beneath the periphery-of said vibratoryaback face 4:, and conveniently secured to itby aplurality of fastening screws 19 which also pass through and secure adowerknifdedgedring-20;

vA :reversely formed upper knife edged ring 21 of greater 5 diameter than the lower ring 20, is conveniently superposed upon a rubberring-22 the diameter of which is about equal to that of the diaphragm, and is pressed upon' the diaphragm and the ring 20 by a plurality of compressed springs 23 which serve to force down the peripheral edges of said diaphragm: against the resistance of said lower knife-edged 'ring .20,-'a rubber ring 24 being conveniently interposed between them .--"-with':the result that by reason of the differentdiametric proportions of .the-itwo knifeeedged-rings any. desired bulge maybefimpartedto the diaphragm.

The springs 23 are conveniently-held in placeagainst the upper'surface of the upper knifeeedgedring 21, by 'a retainingring 25 conveniently secured by screws 26 which enter the "wall .17.

' \QfTCOHISG, in this construction iniwhichv a bulge. of the diaphragnimay beoccasioned by the coactionnf the knife-edgedtrin s such rings serve as a compositesepaiiating ring; so

tosspeaknand. efiecti hothzthessepanation and resides in a sound box the rear wall of which the inclosure of the diaphragm and back to form the desired sound chamber.

From the foregoing description it will be understood that the essence of my invention is formed of mica or equivalent vibratory ima-terial and with which is. combined by any prefe red means of peripheral un on, a diaphragm.

The union maybe effected as in the construction of the first four figures, by a mere fastening togetherofthe casing rings 1 and 2, with a simple separating ring between them,or,.as;in the modified construction of Figs. 5, 6 and :7, the sound box may have an inclosing wall 17, and theseparation'of theperipheries of its vibratoryirear wall and of the diaphragm may be effected by the placing between them of the two knife-edged rings, the lower ring 20'subservingthedual purpose of a separating and sound-chamberinclosing ring, wellsas of a circular abutment with reference to which the upper knife-edged ring 21 acts .upon the periphery of the diaphragm to effect its bulge.

The constructions so far as my invention broadly considered is concerned, are the same, because in each'instance'the rearface orzbael r or wall :of-thesound box proper is composed of mica or equivalent =vibratory material and the diaphragm of mica or equivalent vibratory material is so-mou-nted witlrreference to1the vibratory rear face of the casing-astoeftect the formation between them of a sound chamber-withinwhieh the 100 pulse. vons ofthe'soundwaves-take place and are increased'or reduced in volumeso as to reproduce-vocal, musical and other tonesrof the desired zpitch oricharacter, whichaccurately correspond with the :sound impulses 1 emanating from "the .reco-rd "WhlCh are-to be I reproduced.

k' the connection between the diaphragms as being peripheral, Irlo-not'desireito be under- 12 stood as limiting it to thenexactperipheries, of the elements in the geometrical sense, but simply as being a connection,preferably, but not necessarily;comprisingseparating -means-,-'such as will give to tthei inclosed sound-:chamber a desirable @diamet-ric area, and a distance between the diaphragms sufficient torpermitmf' an adequate vibration of both ofztthem, which,.of ;course,cneed1rno.t

as-rte botheczt then :;be.nfeeqna1.-;extent.

The proportions, general dimensions, and outlines of the elements are also, of course, subject to variations, and the vibratory back may be either flat or dished toward or from the diaphragm proper. I

The thickness of the vibratory substance of which the back is composed may also be varied, having regard to both the necessary strength to secure the mounting of the box as a whole upon the tone or casing tube, and the necessary vibratory quality.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is

1. A sound box, the front and the rear walls of which are both composed of diaphragms connected near their peripheries so as to form between them a sound chamber,a stylus operatively connected with one of said diaphragms,and a tone tube operatively connected with the other.

2. A sound box having its front wall formed by a vibratory diaphragm and its back wall also formed by a vibratory diaphragm,'means to connect said diaphragms in proximity to their peripheries,-a sup-- port between said diaphragms upon which they fulcrum,a stylus operatively connected with the front diaphragm,--and a supporting tone tube operatively connected with the back diaphragm. a

3. A sound box formed by a front dia phragm and a rear diaphragm emeans for connecting said diaphragms near their pefulcrum,a stylus operatively connected with the front diaphragm,and a tone tube operatively connected with the rear diaphragm.

5. A sound box which comprises a front diaphragm,a stylus operatively connected with said front diaphragm,a; second diaphragm which constitutes the back of the sound box and which is peripherally connected with the front diaphragm so as to form between them an inclosed sound chamber,-and a tone tube to an opening in which the back diaphragm is connected.

In testimony that I claim the foregoing as my'invention, I have hereunto this 14th day of April, 1920, signed my name.

MAX KRA ss.

Witnesses i J. 'BoNsALL TAYLOR, JOHN A. WIEDERSHEIM. 

